(S)-2-{(2S,3S)-3-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-2-fluoro-propionyl chloride 、 以
乙腈 为溶剂,
以81%的产率得到(S)-4-{(2S,3S)-3-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-4-oxo-azetidin-2-yl}-4-fluoro-3-oxo-pentanoic acid 4-nitro-benzyl ester